منابع مشابه
Learning Acyclic First-order Horn Sentences
This paper considers the problem of learning an unknown rst-order Horn sentence H from examples of Horn clauses that H either implies or does not imply. Particularly, we deal with a subclass of rst-order Horn sentences ACH(k), called acyclic constrained Horn programs of constant arity k. ACH(k) allows recursions, disjunctive definitions, and the use of function symbols. We present an algorithm ...
متن کاملReduced Products, Horn Sentences, and Decision Problems
We shall consider a first order language with equality, and the corresponding structures. Reduced products {powers) and Horn sentences are defined in [4, pp. 199, 211]. An Vn sentence is a prenex sentence whose prefix consists of a block of universal quantifiers, followed by a block of existential quantifiers, followed by another block of universal quantifiers, and so on n times; an sentences a...
متن کاملFatal Heyting Algebras and Forcing Persistent Sentences
Hamkins and Löwe proved that the modal logic of forcing is S4.2. In this paper, we consider its modal companion, the intermediate logic KC and relate it to the fatal Heyting algebra HZFC of forcing persistent sentences. This Heyting algebra is equationally generic for the class of fatal Heyting algebras. Motivated by these results, we further analyse the class of fatal Heyting algebras.
متن کاملLearning Acyclic First-Order Horn Sentences from Entailment
This paper consider the problem of learning an unknown rst-order Horn sentenceH from examples of Horn clauses that H implies and does not imply. Particularly, we deal with a subclass of rst-order Horn sentences ACH(k), called acyclic constrained Horn programs of constant arity k. ACH(k) allow recursions, disjunctive de nitions, and the use of function symbols. We present an algorithm that exact...
متن کاملOn Theorem-Proving in Horn Theories with Built-in Algebras
We present a semi-decision procedure to prove ground theorems in Horn theories with built-in algebras. This is a maximal-unit-strategy based method, i.e in all our inference rules at least one of the premises clauses is an unit one. As in 4], constraint formalism is used as well ; but more general speciications are studied. To limit the search space, an rpo-like ordering is used. Neither uniica...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1997
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(97)00019-8